The explosions came as Christmas shoppers crowded in a busy pedestrian quarter of the Swedish capital.

A manSwedish investigators suspect may have been the bomber was killed in the blasts, while a separate explosion nearby injured two people.

Islamist website Shumukh al-Islam named Taymour Abdel Wahab as the man responsible for the explosions, which Sweden has said it is probing as a "terrorist crime."

The site said: "It is our brother, mujahid Taymour Abdel Wahab, who carried out the martyrdom operation in Stockholm."

Sweden's intelligence agency Saepo has refused to confirm or deny that the man identified by the website was the bomber.

The Daily Telegraph discovered that he studied at the University of Bedfordshire in Luton, around 30 miles north of London, and had continued living in the town in recent years.

The wife and children of Taymour Abdel Wahab - said to be in his late 20s - are still living in Luton.

He has been described as an Iraqi-born Swede who moved from Iraq to Scandanavia when he was 11. He came to Britain in 2001 to study sports therapy at the University of Luton, now the University of Bedfordshire.

"I used to see him around often. He didn't say much but seemed nice. I used to see him walking with his kids," Tahir Hussain, 33, a local taxi driver told The Daily Telegraph.

"I was shocked when I heard what happened because I never thought he could do such a thing."

Britain's Home Office, or interior ministry, refused to comment on the reports.

"We remain in close contact with the Swedish authorities," a spokesman said. "It would be inappropriate to comment on an ongoing investigation at this time."

Sweden on Sunday said it was investigating the blasts as a "terrorist crime." Anders Thornberg, head of the security unit of domestic intelligence Saepo, said: "We suspect that it was a suicide attack."